This is the Lectron Pro 3.7V 160mAh 25C LiPo Battery 2-Pack (use in place of EFLB1501S25). These batteries are perfect for the Blade mCX/mSR/mSR X. These batteries are plug-and-play compatible with both the helicopter and the stock charger. 25C continuous discharge rate of 4 amps. These batteries are also ideal for the ParkZone Vapor, Micro Citabria, Cessna 210, Ember, and the Parkzone Sukhoi among other micro planes.